In the background of large-scale wind power connected to the grid，accurately calculating the output power of the wind farm is of utmost importance to the dispatching control and grid safe operation.By taking the mean wind speed and direction measured by masts on the minute-to-hour time horizon level as the inputs，the impact of the geographical distribution of wind turbine and wind turbine commitment on the wake model is studied.A new equivalent wind speed model is proposed according to the wind speed spatial and temporal distribution on the wind farm.Based on the proposed wind speed model，a method for wind power calculation considering the mechanical characteristics and operation status of wind turbines is presented.The feasibility and rationality of the method proposed are verified by simulation results of an actual wind farm's geographical data and wind turbine parameters.